Assembly jig



D 1966 J. N. DE BERNARDIS 3,289,268

ASSEMBLY JIG Filed Oct. 27, 1964 2 Sheets-Sheet 2 INVENTOR JOSEPH N. DEBiRNARD/S ATTORNEY United States Patent 3,289,268 ASSEMBLY JIG Joseph N. DeBernardis, Seneca Falls, N.Y., asslgnor to Sylvania Electric Products Inc., a corporation of Dela- Ware Filed Oct. 27, 1964, Ser. No. 406,734 6 Claims. (Cl. 29--25.19)

This invention generally relates to assembly devices and more particularly to a jig for simultaneously assembling and mechanically converging a plurality of electron guns to form an electron gun mount.

In conventional color cathode ray tubes in use today a plurality of electron guns is arranged to form an electron gun mount which is positioned in the tube opposite a phosphor coated screen. The guns are usually arranged delta fashion, and it is necessary for proper tube operation that the electron beams emanating from the guns be mechanically converged to a point at substantially the shadow mask which is positioned between the gun and the phosphor screen. While it is possible to have the guns parallelly arranged and effect convergence of the beams by magnetic or electrostatic means, it is usually found to be more economical to provide convergence mechanically.

When mechanical convergence is used, it is necessary to provide a jig of some sort to hold the various pieces while the guns are being connected together. Since a color cathode ray tube is a relatively expensive, highly sophisticated component requiring great accuracy in manufacture, it follows that any jig utilized in its fabrication must be constructed with an accuracy consistent with the other requirements of the tube.

Since mechanically converging the electron beams requires that the guns be physically angled away from the centerline of the tube (at an angle of approximately 16 in one current type of tube), problems arise in the jig construction that are not present when the guns are to be parallelly arrayed. For example, it immediately becomes necessary that the gun holding elements be constructed separately so that they may be removed after the mount is assembled.

One type of jig that has been used in the past utilized three mandrels that were inserted into preassembled guns. The bottom portions of the mandrels, which were provided with a predetermined angle, were inserted into a base where they were clamped by a plurality of thumbscrews. Following, a number of supporting discs, usually two, were welded to the guns in various positions thereon to maintain the convergence angle. Then the unit was disassembled and the mandrels removed.

This type of jig had many disadvantages. It was necessary that the guns be preassembled; the mandrels were fixed at only one end thereby not giving constant accuracy; and the use of the supporting discs entailed further operations which added to the cost of the structure.

It is, therefore, an object of this invention to reduce the above-mentioned disadvantages and to improve the fabrication of electron gun mounts.

It is another object of the invention to enhance the accuracy of electron gun mounts by the provision of a new and novel jig structure.

Another object of the invention is the reduction of the number of operations necessary to the manufacture of electron gun mounts.

Still another object of the invention is the provision of an assembly jig that is easy to operate and that is suitable for use with mass production techniques.

The above objects are carried out in one aspect of the invention by the provision of an assembly jig for simultaneously assemblying and mechanically converging a plurality of electron guns to provide an electron gun mount. The jig comprises a base member, a plurality of electron gun holding cartridges adapted at one end thereof to be fitted to the base member, and a top cap adapted to be fitted to the other end of the cartridges.

This jig has many advantages over the prior art structures. It assures consistent accuracy of alignment by securely fastening and maintaining the gun holding cartridges at both ends. By providing means for simultaneously assemblying and converging the guns the number of assembly operations is reduced, thereby reducing the cost. It eliminates a number of previously needed support pieces thereby further reducing the cost, and it is easy to operate and well suited to mass production techniques.

For a better understanding of the present invention, together with other and further objects, advantages, and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the accompanying drawings in which:

FIG. 1 is an elevational view of a typical electron gun mount of a type that may be fabricated utilizing the jig of this invention;

FIG. 2 is a sectional view taken along the line 22 of FIG. 1;

FIG. 3 is an elevational view of the jig of this invention, taken along the line 33 of FIG. 4, with some parts shown in section and others omitted in the interest of clarity;

FIG. 4 is a plan view of the jig taken along the line 4-4 of FIG. 3;

FIG. 5 is an enlarged elevational view, partly in section, of the gun holding cartridge;

FIG. 6 is a sectional view taken along the line 6-6 of FIG. 3; and

FIG. 7 is a sectional view taken along the line 77 of FIG. 3.

Referring now to the drawings with greater particularity, in FIG. 1 there is shown an electron gun mount 10 of a type that can be utilized in a color cathode ray tube. Mount 10 is composed of three (3) electron guns 12, which in turn are composed of a plurality of grid electrodes, generally designated G G G and G and a cathode-heater assembly 14. The cathode-heater assembly 14 is nested within the G and, in operation, provides a beam of electrons which is controlled, focused, and accelerated by proper potentials being applied to the various grid electrodes. The electrodes are substantially all of the same diameter with the exception of the G which has a reduced diameter portion 15 at its upper end which forms shoulder 17, and they are provided with glass bead engaging straps 16 (seen more clearly in FIG. 2) which are formed to engage glass beads 18. The cooperation of straps 16 with beads 18 serves to hold the individual gun elements and the guns in the proper operating position.

Since, as stated above, it is now usual practice to effect convergence of the beams by mechanically converging the guns there will now be described the jig of this invention formed for simultaneously assembling guns and providing the necessary convergence.

Jig 20 is comprised generally of a base member 22, a top cap 24, and a plurality of electron gun holding cartridges 26 disposed therebetween.

Base member 22 comprises a substantially cylindrical, longitudinally extending hub 28 formed to provide a plurality of equidistantly spaced, radially extending arms 30 at one end thereof. While in this instance the number of arms will be three, it will be obvious that they may be increased or decreased to correspond to the number of guns desired in the final mount. Arms 30 are provided with specifically oriented first aligning means 32, such as upstanding pins 34, of any suitable wearresistant material. These pins are firmly fixed in arms by any conventional method. Each of the arms 30 is also provided, at its peripheral edge, with an upstanding wall 36 which is provided with a threaded opening 38, the use of which will be explained hereinafter.

Top cap 24 has substantially the same plan configuration as base member 22 and is comprised of a central hub 40 and three equidistantly spaced, radially extending arms 42. Each of the arms 42 is provided with specifically oriented second aligning means 44, such as depending pins 46. These pins also are firmly fixed in arms 42 by any conventional means. Top cap 24 may also be provided with a handle, such as 48, to provide for easier manual manipulation thereof.

Electron gun holding cartridges 26, which are disposed between base member 22 and top cap 24, each comprise a base block and a top block 52 which are provided with pin receiving apertures 54 and 56, respectively, which matingly engage pins 34 and 46, respectively. Top block clamping means 53, in the form of a thumbscrew, is also provided to securely fasten top The alignment rod 58 and the mandrels 60, 62, 64'

have their axes displaced from the vertical by the convergence angle of the tube in which the finished mount will operate, in this instance 16. To promote accurate construction it should be noted that the upper surface 51 of base block 50 and the lower surface 55 of top block 52 are formed to provide this same angle. This procedure allows pin receiving apertures 54 and 56 to be formed perpendicularly to the surface from which they enter and likewise allows alignment rod 58 and the mandrels 6t), 62, 64 to be perpendicular to the surfaces 51 and 55. Thus the necessity of drilling or otherwise forming holes at an angle, a tricky procedure at best, is avoided and the overall accuracy of the jig is enhanced.

Alignment rod 58 is firmly fixed in base block 50 by any conventional method, as taper pin 66, and is formed to provide, intermediate its ends, slide means 68 for electrode spacers 70, 72, and 74. Slide means 68 comprise square rod sections 76 and spacer retaining collars 78 and may include detent means 79. Detent means 79 comprises displaceable ball 81 and tension providing means 83 (see FIG. 6). Set screw 85 is provided to maintain the means within a bore 87. Notches 89, 89a are formed in spacers 70, 72, and 74 and cooperate with a ball 81 and serve to keep the spacers in a retracted or extended position. Additionally, the upper section of rod 58 is formed to provide axial displacement of top block 52 by allowing both linear and rotatable movement thereof. This is accomplished by a reduced diameter portion 80 about which top block 52 is rotatable and a fiat area 82 on normal diameter portion 84 along which top block 52 is capable of linear movement. Pin 86 in top block 52 rides against flat 82 and prevents rotation thereabout and when top block 52 is raised and rotated, pin 86 rests against shoulder 88 and prevents block 52 from descending inadvertently. Eccentrically mounted collar 90 is fixed to the top of rod 58, as by set screw 92, and prevents top block 52 from being accidentally withdrawn, and it is provided with a downwardly depending pin 94 which arrests rotation of top block 52.

First mandrel 60, which is positioned in base block 50 by any suitable means, such as set screw 96 bearing against reduced diameter portion 98, is formed to provide an electrode retaining collar 100 which has a diameter larger than the inside diameter of the electrodes and a main stem section 102 that has a diam eter slightly less than the inside diameter of the electrodes to allow the electrodes to slidably fit thereover. Friction reducing areas 104 having a diameter less than that of 102 may also be provided.

Third mandrel 64 is slidably mounted within a central bore 106 in first mandrel 60, as may best be seen in FIG. 5, and is restrained in its movement by pin 108 and aperture 110'. Spring 1=12 supplies the necessary tension to mandrel 64 to correct for slight inconsistencies in grid size as will be explained hereinafter. Mandrel 64 is provided at its upper shouldered end 113 with specially diametered portions 114, 116, and 118 which align the G G and G electrodes, respectively. 'It will be apparent that the specific configurations of these portions as they are illustrated is by way of example only and that they will obviously be made to fit the type of grid electrodes being utilized.

Second mandrel 62 is firmly fixed in top block 52 and is formed to align the G electrode which has nested therewithin the cathode-heater assembly 14. Mandrel 62 may be provided with a central bore 120 for receiving the cathode lead 122 and the heater leads if they are present.

Glass bead engaging strap aligning means 124 is also provided to increase the operating efficiency of the jig and comprises a substantially U-shaped portion 126. The legs 128 of portion 126 are formed to provide pairs of strap aligning fingers 130, one pair for each electrode, and they engage the straps 16 'as shown in FIG. 7. Spring clips 132 are provided at the base of U- shaped portion 126 and releasably engage circular portions of alignment rod 58. Cutouts 133 may be provided to allow for expansion of clips 132 if space requirements dictate. A handle 134 may also be provided to increase the ease of manual manipulation.

Cartridge clamping means, which may be in the form of a thumbscrew 136, is threadably engaged in opening 38 and is formed to contact base block 50 'at angled portion 138 thereby providing precise alignment of the cartridges and holding the same firmly in position.

In use, an operator will first load the cartridges 26. This is accomplished by raising top block 52 to reduced diameter portion 80 on alignment rod 58 and rotating it approximately A G; electrode is placed on mandrel 60 and lowered until it rests upon retaining collar 100. Spacer 70 is then urged past detent means 79 and positioned over the G electrode. The G electrode is then threaded ove-r mandrel 60 and lowered until its closed end rests upon the upper shoulder 113 of third mandrel 64. Specifically diametered portions 116 and 118 project upwardly through the electron beam aperture which is provided in the closed ends of the G G and G electrodes. Spacer 72 is then urged pas-t its detent 79 and into position on G shoulder 17. Next, the G electrode is fitted over portion 118 and lowered until it rests upon spacer 72. Spacer 74 is urged past its detent 79 and into position over G The G with its nested cathode-heater assembly therein is then positioned on second mandrel 62, the cathode lead 122, and heater leads, if present, being inserted into aperture 120 to avoid being bent or broken.

Top block 52 with associated mandrel 62 is then rotated around reduced diameter portion 80 to its linearly movable position and it is then lowered until it contacts spacer 74. When properly aligned, portion 118 will penetrate the beam aperture sufficiently to maintain alignment while not contacting the emissive material on the nested cathode. Downward pressure is then applied to top block 52 sufiicient to overcome the resistance of spring 112 and insure that all electrodes are properly positioned by their respective spacers regardless of slight inconsistencies in electrode size. Top block clamping means 53 is then tightened to maintain the electrodes in this position. Finally, strap aligning means 124 is placed in position, this action aligning the glass bead engaging straps 16 so that a subsequent operation may be performed thereon. The completed cartridge is then positioned on base member 22 with pins 34 engaging apertures 54.

The above-described operation is repeated until the proper number of cartridges has been assembled on base member 22, in this instance three, and then top cap 24 is applied. when it is ascertained that top cap 24 is properly seated, the cartridge clamping means 138 are tightened and the mount is ready to be headed.

After the beading operation has been performed the jig is disassembled by reversing the procedure outlined above leaving a completely assembled and properly converged mount.

The advantages of this jig over those of the prior art are apparent from the above description. The jig is solid and provides consistent alignment. It reduces the number of pieces used and the number of assembly operations needed to form the guns, and it is well suited to mass production techniques.

While there has been shown and described what is at present considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

What is claimed is:

1. An assembly jig for simultaneously assembling and mechanically converging a plurality of electron guns to provide an electron gun mount, said jig comprising: a base member formed to provide a plurality of specifically oriented first aligning means; a top cap formed to provide a plurality of specifically oriented second aligning means; a plurality of electron gun holding cartridges disposed between said base member and said top cap, said cartridges each comprising a base block and a top block formed to matingly engage said first aligning means and said second aligning means respectively, and an alignment rod disposed between said blocks and cooperatively connected thereto, and first and second mandrels disposed between said blocks, said first mandrel being afiixed to said base block and said second mandrel being affixed to A said top block; and cartridge clamping means formed on said base member where-by precise alignment of said cartridges and guns is maintained.

2. An assembly jig for simultaneously assembling and mechanically converging a plurality of electron guns to provide an electron gun mount, saidji-g comprising: a base member formed to provide a plurality of specifically oriented first aligning means; a top cap formed to provide a plurality of specifically oriented second aligning means; a plurality of electron gun holding cartridges disposed between said base member and said top cap, said cartridges each comprising a base block and a top block formed to matingly engage said first aligning means and said second aligning means respectively, an alignment rod disposed between said blocks and cooperatively connected thereto, and first, second and third mandrels disposed between said blocks, said first mandrel being aflixed to said base block, said second mandrel being aflixed to said top block, and said third mandrel being mounted for limited axial movement within said first mandrel; and cartridge clamping means formed on said base member whereby precise alignment of said cartridges and guns is maintained.

3. An assembly jig for simultaneously assembling and mechanically converging a plurality of electron guns to provide an electron gun mount, each of said guns comprising a cathode and a number of normally spaced apart grid electrodes with said cathode being nested in one of said grid electrodes, said jig comprising: a base member formed to provide a plurality of specifically oriented first aligning means; a top cap formed to provide a plurality of specifically oriented second aligning means; a plurality of electron gun holding cartridges disposed between said base member and said top cap, said cartridges each comprising a base block and a top block formed to matingly engage said first aligning means and said second aligning means respectively, an alignment rod disposed between said blocks and cooperatively connected thereto, first and second electrode receiving mandrels adjacent said alignment rod, said first mandrel being fixed to said base block and said second mandrel being fixed to said top block, and electrode spacing means on said alignment rod movable into and out of engagement with said mandrels; said top block being linearly movable from a first position on said alignment rod to a second position on said rod and ro-' tatably movable from said second position to a third position; means fixed to the end of said rod to arrest movement of said top block, clamping means on said top block; and cartridge clamping means formed on said base member whereby precise alignment of said cartridges and guns is maintained.

4. An assembly jig for simultaneously assembling and mechanically converging a plurality of electron guns to provide an electron gun mount, each of said guns comprising a cathode and a number of normally spaced apart grid electrodes with said cathode being nested in one of said grid electrodes, said grid electrodes being formed to provide glass bead engaging straps, said jig comprising: a base member formed to provide a plurality of specifically oriented first aligning means; a top cap formed to provide a plurality of specifically oriented second aligning means; a plurality of electron gun holding cartridges disposed between said base member and said top cap, said cartridges each comprising a base block and a top block formed to matingly engage said first aligning means and said second aligning means respectively, an alignment rod disposed between said blocks and cooperatively connected thereto, first and second electrode receiving mandrels adjacent said alignment rod, said first mandrel being fixed to said base block and said second mandrel being fixed to said top block, and electrode spacing mean on said alignment rod movable into and out of engagement with said mandrels; means for aligning said glass bead engaging straps; said top block being linearly movable from a first position on said alignment rod to a second position on said alignment rod and rotatably movable from said second position to a third position; means fixed to the end of said rod to arrest movement of said top block, clamping means on said top block; and cartridge clamping means formed on said base member whereby precise alignment of said cartridges and guns is maintained.

5. An assembly jig for simultaneously assembling and mechanically converging a plurality of electron guns to provide an electron gun mount, each of said guns comprising a cathode and a number of normally spaced apart grid electrodes with said cathode being nested in one of said grid electrodes, said jig comprising: a base member formed to provide a plurality of specifically oriented first aligning means; a top cap formed to provide a plurality of specifically oriented second aligning means; a plurality of electron gun holding cartridges disposed between said base member and said top cap, said cartridges each comprising a base block and a top block formed to matin-gly engage sai-d first aligning means and said second aligning means respectively, an alignment rod disposed between said blocks and cooperatively connected thereto, first and second electrode receiving mandrels adjacent said alignment rod, said first mandrel being fixed to said base block and said second mandrel being fixed to said top block, and electrode spacing means on said alignment rod movable into and out of engagement with said mandrels; detent means on said alignment rod formed to releasably hold said spacing means in a position remote from said mandrels; said top block being linearly movable from a first position on said alignment rod to a second position on said rod and rotatably movable from said second position to a third position, means fixed to the end of said rod to arrest movement of said top block, clamping means on said top block; and cartridge clamping means formed on said base member whereby precise alignment of said cartridges and said guns is maintained.

6. An assembly jig for simultaneously assembling and mechanically converying a plurality of electron guns to provide an electron gun mount, each of said guns comprising a cathode and a number of normally spaced apart grid electrodes with said cathode being nested in one of said grid electrodes, said grid electrodes being formed to provide glass bead engaging straps, said jig comprising: a base member formed to provide a plurality of specifically oriented first aligning means; a top cap formed to provide a plurality of specifically oriented second aligning means; a plurality of electron gun holding cartridges disposed between said base member and said top cap, said cartridgeseach comprising a base block and a top block formed to matingly engage said first aligning means and said second aligning means respectively, an alignment rod disposed between said blocks and cooperatively connected thereto, first, second, and third electrode receiving mandrels having a longitudinal axis adjacent said alignment rod, said first mandrel being fixed to said base block, said second mandrel being fixed to said top block, and said third mandrel being mounted Within said first mandrel and being movable therein along said longitudinal axis, and electrode spacing means on said alignment rod movable into and out of engagement with said mandrels; and means for clamping said cartridges to said base member whereby precise alignment of said cartridges and guns is maintained.

References Cited by the Examiner UNITED STATES PATENTS 2,829,941 4/1958 Laubscher 29-203 X 2,914,317 11/1959 Miller 269-40 JOHN F. CAMPBELL, Primary Examiner.

WILLIAM I. BROOKS, Examiner. 

1. AN ASSEMBLY JIG FOR SIMULTANEOUSLY ASSEMBLING AND MECHANICALLY CONVERGING A PLURALITY OF ELECTRON GUNS TO PROVIDE AN ELECTRON GUN MOUNT, SAID JIG COMPRISING: A BASE MEMBER FORMED TO PROVIDE A PLURALITY OF SPECIFICALLY ORIENTED FIRST ALIGNING MEANS; A TOP CAP FORMED TO PROVIDE A PLURALITY OF SPECIFICALLY ORIENTED SECOND ALIGNING MEANS; A PLURALITY OF ELECTRON GUN HOLDING CARTRIDGES DISPOSED BETWEEN SAID BASE MEMBER AND SAID TOP CAP, SAID CARTRIDGE EACH COMPRISING A BASE BLOCK AND A TOP BLOCK FORMED TO MATINGLY ENGAGE SAID FIRST ALIGNING MEANS AND SAID SECOND ALIGNING MEANS RESPECTIVELY, AND AN ALIGNMENT ROD DISPOSED BETWEEN SAID BLOCKS AND COOPERATIVELY CONNECTED THERETO, AND FIRST AND SECOND MANDRELS DISPOSED BETWEEN SAID BLOCKS, SAID FIRST MANDREL BEING AFFIXED TO SAID BASE BLOCK AND SAID SECOND MANDREL BEING AFFIXED TO SAID TOP BLOCK; AND CARTRIDGE CLAMPING MEANS FORMED ON SAID BASE MEMBER WHEREBY PRECISE ALIGNMENT OF SAID CARTRIDGES AND GUNS IS MAINTAINED. 